In semiconductor manufacturing, semiconductor wafers often undergo many processing steps or stages before a completed die is formed. For example, thermal processing is often performed on wafers for various purposes, such as Shallow Trench Isolation (STI), repairing film defects, dopant activation from ion implantations, and film property transformation, among others.
Bulk Micro Defects (BMDs) may be further induced by thermal processing, as proven useful in semiconductor processing for metal contamination gathering effects. Although BMDs may provide the advantageous metal gathering effect, the thermal processing associated with the formation of the BMDs also has a tendency to reduce wafer strength, which can lead to undesirable wafer distortion (warping), substrate lattice dislocation, and/or broken wafers which lead to failures of the wafer and lower yields of final products.
Conventional methods for maintaining wafer strength have been primarily limited to controlling an overall oxygen concentration and crystalline defect densities across an entire semiconductor ingot during the ingot preparation process.